[C320-list] Yanmar 3GM30F Exhaust Elbow/Riser

[Allan Field]

Dennis - My recommendation would be to contact a Yanmar dealer directly,
such as Bay Shore Marine in Annapolis, MD, and work with them for a
replacement. On our old C320, they furnished a perfect drop-in replacement.

Allan S. Field
Sea Shadow - C387, #103 (formerly C320, #808)
Columbia, MD

On Wed, Mar 24, 2021 at 5:33 PM Dennis Cookson <dennis at cooksons.net> wrote:

> I am thinking about replacing, or at least inspecting, the exhaust elbow
> on our 1999 Yanmar 3GM30F as its age and condition are unknown. It seems to
> be a non-standard construction, unlike any Yanmar part I can find, with a
> U-shaped riser which is fully insulated with a woven thermal sleeve of
> unknown material, possibly fibreglass.
>
> I’ve uploaded a photo of this elbow/riser <
> https://c320.org/mediagallery/media.php?f=0&sort=0&s=20210324212234253>
> to the Technical Photos gallery.
>
> It roughly resembles the shape of the “Exhaust Riser C-320”  on the
> Catalina Direct web site which I see is made of stainless steel. The raw
> water inlet to this riser is located well away from the exhaust manifold,
> on the downhill side of the ‘U’ close to the connection to the rubber hose
> that leads to the waterlift.  The fact that the riser has to be insulated
> makes me wonder if the water is actually used to cool the pipe, i.e. is it
> essentially a dry riser where water is not used for cooling but just for
> reducing exhaust noise.  In this case, perhaps there is less risk of a
> failure causing water to enter the
>
> I’d be grateful for any advice or information re the following questions:
>
> - is this part prone to catastrophic failure from internal corrosion, in
> the same way that the original Yanmar mixing elbows are?  Anyone had that
> experience?
> - what lifetime in terms of age or engine hours can reasonably be expected?
> - if it needs to be replaced, must it be replaced with a similar custom
> part like the one on Catalina Direct, or it is ok to use the Yanmar
> 128370-13610 Mixing Elbow Riser Kit? This has a much tighter bend with
> water input very close to the manifold.  (I’m assuming that the riser needs
> to reach a specific height above the water level at all angles of heel -
> this arrangement would be more compact.)
>
> Dennis Cookson
> Catalina #577
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